Polysulfides, di-tert-Bu

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-09-04 to 2012-11-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP in accordance with recognised guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not applicable

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

not applicable

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Details on test material:

- Description: amber colored liquid- Purity: not applicable - complex mixture- Expiry / Retest Date: 25 August 2013- Storage Conditions: room temperature in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Water samples were taken from the control and each loading rate WAF test group (replicates R1 - R4 pooled) at 0 and 48 hours for quantitative analysis. Samples were stored at approximately -20 °C prior to analysis. Duplicate samples were taken and stored at approximately -20 °C for further analysis if necessary.

Test solutions

Vehicle:

no

Details on test solutions:

Amounts of test item (25, 45, 80, 140 and 250 mg) were each separately added to the surface of 2.5 liters of reconstituted water to give the 10, 18, 32, 56 and 100 mg/L loading rates respectively. After the addition of the test item, the reconstituted water was stirred by magnetic stirrer using a stirring rate such that a vortex was formed to give a dimple at the water surface. The stirring was stopped after 23 hours and the mixtures allowed to stand for 1 hour. A wide bore glass tube, covered at one end with Nescofilm was submerged into the vessel, sealed enddown, to a depth of approximately 5 cm from the bottom of the vessel. A length of Tygon tubing was inserted into the glass tube and pushed through the Nescofilm seal. Microscopic inspection of the WAFs showed no micro-dispersions or undissolved test item to be present. The aqueous phase or WAF was removed by mid-depth siphoning (the first approximate 75-100 mL discarded) to give the 10, 18, 32, 56 and 100 mg/L loading rate WAFs. The concentration and stability of the test item in the test preparations were verified by chemical analysis at 0 and 48 hours.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM- Common name: Water Flea (Daphnia)- Strain: Daphnia magna- Source: In house laboratory cultures- Age at study initiation : less than 24 hours old- Method of breeding: parthenogenises- Feeding during test: The daphnids received no food during exposure

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

none

Test conditions

Hardness:

The reconstituted water had an approximate theoretical total hardness of 250 mg/l as CaCO3.

Test temperature:

The temperature was maintained at 20-21°C throughout the duration of the test.

pH:

pH 7.8 to 8.1

Dissolved oxygen:

The dissolved oxygen concentration was approximately air-saturation value

Salinity:

Not applicable

Nominal and measured concentrations:

Based on the results of the range-finding test the following loading rates were assigned to the definitive test: 10, 18, 32, 56 and 100 mg/L.

Details on test conditions:

TEST SYSTEM- Test vessel: 250 ml covered jar - Material: glass - Aeration: No- No. of organisms per vessel: 5- No. of vessels per concentration (replicates): 4- No. of vessels per control (replicates): 4TEST MEDIUM / WATER PARAMETERS- Source/preparation of dilution water: reconstituted water- Conductivity: <5 μS cm-1- Culture medium different from test medium: No difference- Intervals of water quality measurement: N/AOTHER TEST CONDITIONS- Adjustment of pH: Using NaOH or HCl were necessary- Photoperiod: 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods- Light intensity: 811 to 849 luxEFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The criterion of effect used was that Daphnia were considered to be immobilised if they were unable to swim for approximately 15 seconds after gentle agitation.TEST CONCENTRATIONS- Spacing factor for test concentrations: 10- Range finding study - Test concentrations: 10, 18, 32, 56, 100 mg/l - Results used to determine the conditions for the definitive study: No significant immobilization was observed at 10 mg/L loading rate WAF. However, immobilization was observed at 100 mg/L loading rate WAF.

Reference substance (positive control):

yes

Remarks:

potassium dichromate (non-concurrent)

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

63 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% Cl = 52 - 77 mg/l

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

18 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks:

immobilisation

Effect concentrations 3

Duration:

48 h

Dose descriptor:

LOELR

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks:

immobilisation

Details on results:

- Behavioural abnormalities: none- Observations on body length and weight: none- Other biological observations: A decline in measured test concentrations was observed at 48 hours to 0.0068 and 0.13 mg/L for the 10 and 00 mg/L loading rate WAF test preparations respectively indicating that the test item was unstable over the test period.- Mortality of control: The No Observed Effect Concentrations after 24 and 48 hours were 0.56 and 0.32 mg/L respectively. The No Observed Effect Concentration is based upon zero immobilization at this concentration.- Other adverse effects control: none- Abnormal responses: NDA- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: NDA- Effect concentrations exceeding solubility of substance in test medium: N/A

Results with reference substance (positive control):

- Results with reference substance valid? YesThe results from the positive control with potassium dichromate were within the normal range for this reference material. The mean 48-Hour EC50 value calculated from all positive controls was 0.45 - 0.75 mg/l (sd = ADD).The No Observed Effect Concentrations after 24 and 48 hours were 0.56 and 0.32 mg/L respectively. The No Observed Effect Concentration is based upon zero immobilization at this concentration.Time (h) 24EC50 (mg/l) = 0.7595% Confidence limits (mg/l) = 0.56 - 1Time (h) 48EC50 (mg/l) = 0.4595% Confidence limits (mg/l) = 0.42 - 0.48

Any other information on results incl. tables

TABLE 1 : Cumulative Immobilization Data in the Definitive Test (see attached background material)

TABLE 2: Cumulative Immobilization Data in the Range-finding Test (see attached background material)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EL*50 value of 63 mg/L loading rate WAF; 95% confidence limits 52 - 77 mg/L loading rate WAF. The No Observed Effect Loading rate at 48 hours was 18 mg/L loading rate WAF. The Lowest Observed Effect Loading rate at 48 hours was considered to be 32 mg/L loading rate WAF.

Executive summary:

Method and material

A study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphnia sp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008. Methods Due to the low aqueous solubility and complex nature of the test item, for the purposes of the test, the test item was prepared as a Water Accommodated Fraction (WAF).

Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to Water Accommodated Fractions (WAFs) of the test item over a range of nominal loading rates of 10, 18, 32, 56 and 100 mg/L for 48 hours at a temperature of 20 °C to 21 ºC under static test conditions. The number of immobilized Daphnia and any adverse reactions to

exposure were recorded after 24 and 48 hours.

Results

The 48-Hour EL*50 for the test item to Daphnia magna based on nominal loading rates was 63 mg/L; 95% confidence limits 52 - 77 mg/L loading rate WAF. The No Observed Effect Loading rate was 18 mg/L loading rate WAF. The Lowest Observed Effect Loading rate was considered to be 32 mg/L loading rate WAF. Analysis of the test preparations at 0 hours showed measured test concentrations to range from 0.028 to 0.85 mg/L. A decline in measured test concentration was observed at 48 hours in the

range of less than the limit of quantitation (LOQ) of the analytical method employed (which was determined to be 0.0050 mg/L) to 0.16 mg/L.

Given that the toxicity cannot be attributed to a single component or a mixture of components, but to the test item as a whole, and the dissolved test item was below the quantifiable limit of the analytical method, the results were based on nominal loading rates only.